Improvement in metallic cartridges



W. BAKEWELL.

' Cartridge.

No. 39,109.. Patented July 7, 1863.

mine we UNIT D STATES PATEN QFFIdEQ \VILLIAM BAKEWELL, OF PITTSBURG, PENNSYLVANIA.

IMPROVEMENT IN METALLIC CARTRIDGES.

Specification forming part of Letters Patent No. 39,109, dated July 7, 1863.

To all whom it may concern Be it known that I, WILLIAM BAKEWELL, of the city of Pittsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Metallic Cartridges for Fire-Arms; and I do hereby declare the following to be a full, clear, and exact description thereof, reference being had to the annexed drawing, forming part of this specification.

My invention is designed to facilitate and insure the easy-removal of the metallic case from the charge-chamber or breech of a firearm at'ter firing, and is applicable to metallic cartridges, whether so constructed asto load from the front or from the rear, in revolvers, rifles, or other fire-arms in which cartridges may be employed.

In metallic cartridges as heretofore constructed, the case containing the powder and holding the ball is made of cylindrical or conical shape, and usually of such diameter as to fit more or less closely into the chamber or breech of the fire-arm. The metallic case, being usually made of thin copper, brass, or other ductile metal, will expand more or less by the force of the explosion on firing, and will then press so closely against the surrounding chamber as to render it difficult to remove it. This is especially the case with metallic cartridges so constructed as to be loaded, from the front of the fire-arm, and which, therefore, cannot be drawn out from behind, as the open mouth of the cartridgecase, after firing, presents no good opportunity for seizing the case to pull it forward, and its position in the breech of the piece renders it difficult to reach from the front. Even in the fire-arms which load from the rear, or which are otherwise breech-loading, the same difiiculty of removing the exploded cartridge exists to a great extent.

Myinvention consists in making the metallic cartridge-case, whether tapering or of uniform diameter throughout, of such shape that a cross-section at right angles to its axis will be an ellipse, square, hexagon, octagon, or other curved or polygonal shape, the circumference of which will be less than the circumference of a circumscribed circle, touching the extremities of the figure.

The eflieiency of this construction of the longest diameter of such cartridge-case depends on the fact in mathe-.

in physics that the explosive forceof the,

powder inside of the cartridge-case, pressing in all directions from its axis outward toward its circumference tends to cause any figure other than a circle to assume a form more nearly approaching that of a circle; and thus reduces the long diameter or diameters of such elliptical or polygonal figure. If,

therefore; a cartridge-case, the cross-section of which is elliptical, triangular, or square, be inserted in the breech or charge-chamber of a firearm, the long diameter of the ellipse or the diagonal of the polygon being equal to the diameter of the circular bore of the charge chamber, such cartridge case will fit tightly in the charge-chamber, but when the piece is fired the explosion tends to increase the short diameter of the ellipse and decreases its long diameter, whereby the cartridge-case becomes loose and will drop out of its place; and so of the square or other polygon, the diagonal is reduced in length .by the swelling out of the plane sides, and the same result ensues.

In the accompanying drawing I have represented my cartridge so constructed as to load from the front, having a nipple at the rear end for a percussion cap; but my invention is susceptible of application to metallic cartridges irrespective of the means by which they are fired.

In the drawing accompanying this specifica tion, Figure 1 is a perspective representation -of my improved cartridge-case when made square, the ball being removed. Fig. 2 represents my cartridge-case when of elliptical shape, without the ball. Fig. 3 is a longitudi'nalsection through my improved cartridge and a charge-chamber of a fire-arm loaded therewith. Fig. 4 is a transverse section through the charge-chamber and square cartridge-case before the charge is exploded. Fig. 5 is a transverse section through the charge-chamber and square cartridge-case after the piece is fired, showin g the effect ot the explosion on the square cartridge-case to loosen it in the chamber. Fig. 6 is a trans.

In the drawing, a is the cartridge-case,

drawn, or otherwise constructed, out of copper, brass, or other suitable material. In Fig. 1 it has a square body, the corners being slightly rounded, so as to give the case a firmer hold inside of the charge-chamber, the diagonal diameter, or w, bcingthe same as the interior diameter of the charge-chamber into which it is to be inserted. This case is made of metal, so thin as to be swelled out by the explosion of the charge of powder inserted in it, but not thin enough to be rent or torn thereby. This medium is easily attained, as, unless very thin, the sheet brass or copper is not likely to burst. The rear end a of the cartridge-case is circular, the diameter of the circle being somewhat less than that of the charge-chamber of the firearm, excepting where there is a projecting flange on the rear end of the cartridge, as is the case where they are to be inserted from the rear, and then the body of the case where it unites with the flange is, as described, a circle rather smaller than the diameter of the chamber. The ball I) is fitted into the open end of the cartridgecase, which is previously filled with powder, in the usual way, that portion of the ball which is inserted in the cartridge-case being cast square or other shape corresponding with that of the cartridge-case.

The cartridge may either be provided with a nipple for a percussion-cap or be otherwise provided with t'ulminate for the purpose of firing in any way that may be'desired.

In Fig. 2 the cartridge-case a is represented as having an elliptical body, the long diameter a a being equal to the diameter of the bore of the charge-chamber, and its transverse diameter y y being smaller. The cartridge is otherwise constructed as in Fig. 1, the rear end 0 being circular, but of smaller diameter than the bore of the charge-chamber of the fire-arm.

I have shown only the square and elliptical shapes of cartridge-case, as they exhibit the principle involved, but it is obvious that they might be made of triangular, hexagonal, or other shape, provided that the periphery be less than that of the circumscribed circle, so that when swelled out by the explosion of the charge the sides shall not fill the cavity or bore of the fire-arm.

These cartridge-cases may be readily made, either by drawing them out of the required shape, or forming them round in the usual way, and afterward making them elliptical, square, or other shape, on a mandrel.

The operation of my improved cartridge is manifest from what has been already said. When the pistol or other fire-arm is fired and the cartridge exploded, the elliptical cartridgecase will be forced to assume a shape nearly, if not quite, cylindrical, by the forcing out of the sides in the direction of the. short diameter,

which will cause a corresponding reduction of the length of the long diameter, and as the periphery is less than that of the bore of the chamber, the result will be that the cartridgecase will become loose and can be readily removed. So also with the cartridge-case when made square, triangular, or polygonal; the swelling out of the plane sides will draw the angular corners toward the axis of the cartridge-case, and produce a similar result in its diagonal diameter.

Having thus described my improvement, what Iclaim as my invention, and desire to secure by Letters Patent, is-

The use of metallic cartridges, so constructed that that portion of the case which enters the charge-chamber or breech of the fire-arm (whether tapering or having its sides parallel to its axis) shall be of such shape that a cross-section at right angles to its axis will be an ellipse, triangle, square, or other curved or polygonal figure, the perimeter of which will be less than the circumference of a circumscribed circle, so that the cartridge, fitting closely in the charge-chamber when the pieceis loaded, shall by the expansive force of the discharge have its longest diameter reduced sufficiently to loosen it when the piece is fired, substantially 'as hereinbefore described.

In testimony whereof, I have hereunto set my hand in presence of two subscribing witnesses.

W. BAKEWELL.

Witnesses:

J. D. HANCOCK, J. O. ATTERBURY. 

